This invention pertains to a novel bellows member, and to a unique method of making such a bellows member. In addition, this invention pertains to a pulsation dampener having the novel bellows member.
Bellows are formed in a variety of ways depending upon material. Generally, whether the material is metal, plastic or elastomeric, the wall of the bellows have a convoluted cross sectional configuration to provide for expansion and contraction. A metal bellows can be formed to shape by dies or molds operated by hydraulic pressure. Rubber or like elastomer can be blow molded to form a bellows. Some plastics cannot be blow molded or compression molded to form a bellows, but can be machined. However, such machining of a plastic bellows is labor intensive and therefore costly.
Thus, an object of the present invention is to create a novel plastic bellows that can be injection molded at reasonable cost.
Another object of this invention is to provide a novel bellows having a body with a relatively thin annular wall open at one end and closed at the other, with the wall formed with as a spiral groove convolution.
Yet another object of this invention is to provide a chemically resistant bellows for a variety of fluid handling applications, for example, in a pulsation dampener for a fluid system, said bellows comprising a unitary injection molded body having an annular wall with a corkscrew or spiral shaped convolution configuration.
A further object of the present invention is to provide a bellows having a unitary body with a relatively thin wall formed as a spiral groove and at least one protective layer, the wall of the protective layer being complementary to the wall of the body and being connected to the body by screwing same onto said body.
Other objects and advantages of this invention will be made more apparent in the following description.